Calculation:

If the 2 angles and the non-included side of one triangle is congruent to the 2 angles and non-included side of another triangle, then the two triangles are congruent.

Label the diagram given:

Angle A is congruent to angle C and angle BDA is congruent to angle CDA.

According to the reflexive property of congruence, line BD is congruent to BD.

Therefore,

\(\displaystyle\triangle{B}{D}{A}\stackrel{\sim}{=}\triangle{B}{D}{C}\) (AAA Congruence Theorem).